// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE

(function(mod) {
    if (typeof exports == "object" && typeof module == "object") // CommonJS
        mod(require("../../lib/codemirror"), require("./foldcode"));
    else if (typeof define == "function" && define.amd) // AMD
        define(["../../lib/codemirror", "./foldcode"], mod);
    else // Plain browser env
        mod(CodeMirror);
})(function(CodeMirror) {
    "use strict";

    CodeMirror.defineOption("foldGutter", false, function(cm, val, old) {
        if (old && old != CodeMirror.Init) {
            cm.clearGutter(cm.state.foldGutter.options.gutter);
            cm.state.foldGutter = null;
            cm.off("gutterClick", onGutterClick);
            cm.off("change", onChange);
            cm.off("viewportChange", onViewportChange);
            cm.off("fold", onFold);
            cm.off("unfold", onFold);
            cm.off("swapDoc", onChange);
        }
        if (val) {
            cm.state.foldGutter = new State(parseOptions(val));
            updateInViewport(cm);
            cm.on("gutterClick", onGutterClick);
            cm.on("change", onChange);
            cm.on("viewportChange", onViewportChange);
            cm.on("fold", onFold);
            cm.on("unfold", onFold);
            cm.on("swapDoc", onChange);
        }
    });

    var Pos = CodeMirror.Pos;

    function State(options) {
        this.options = options;
        this.from = this.to = 0;
    }

    function parseOptions(opts) {
        if (opts === true) opts = {};
        if (opts.gutter == null) opts.gutter = "CodeMirror-foldgutter";
        if (opts.indicatorOpen == null) opts.indicatorOpen = "CodeMirror-foldgutter-open";
        if (opts.indicatorFolded == null) opts.indicatorFolded = "CodeMirror-foldgutter-folded";
        return opts;
    }

    function isFolded(cm, line) {
        var marks = cm.findMarks(Pos(line, 0), Pos(line + 1, 0));
        for (var i = 0; i < marks.length; ++i)
            if (marks[i].__isFold && marks[i].find().from.line == line) return marks[i];
    }

    function marker(spec) {
        if (typeof spec == "string") {
            var elt = document.createElement("div");
            elt.className = spec + " CodeMirror-guttermarker-subtle";
            return elt;
        } else {
            return spec.cloneNode(true);
        }
    }

    function updateFoldInfo(cm, from, to) {
        var opts = cm.state.foldGutter.options, cur = from;
        var minSize = cm.foldOption(opts, "minFoldSize");
        var func = cm.foldOption(opts, "rangeFinder");
        cm.eachLine(from, to, function(line) {
            var mark = null;
            if (isFolded(cm, cur)) {
                mark = marker(opts.indicatorFolded);
            } else {
                var pos = Pos(cur, 0);
                var range = func && func(cm, pos);
                if (range && range.to.line - range.from.line >= minSize)
                    mark = marker(opts.indicatorOpen);
            }
            cm.setGutterMarker(line, opts.gutter, mark);
            ++cur;
        });
    }

    function updateInViewport(cm) {
        var vp = cm.getViewport(), state = cm.state.foldGutter;
        if (!state) return;
        cm.operation(function() {
            updateFoldInfo(cm, vp.from, vp.to);
        });
        state.from = vp.from; state.to = vp.to;
    }

    function onGutterClick(cm, line, gutter) {
        var state = cm.state.foldGutter;
        if (!state) return;
        var opts = state.options;
        if (gutter != opts.gutter) return;
        var folded = isFolded(cm, line);
        if (folded) folded.clear();
        else cm.foldCode(Pos(line, 0), opts.rangeFinder);
    }

    function onChange(cm) {
        var state = cm.state.foldGutter;
        if (!state) return;
        var opts = state.options;
        state.from = state.to = 0;
        clearTimeout(state.changeUpdate);
        state.changeUpdate = setTimeout(function() { updateInViewport(cm); }, opts.foldOnChangeTimeSpan || 600);
    }

    function onViewportChange(cm) {
        var state = cm.state.foldGutter;
        if (!state) return;
        var opts = state.options;
        clearTimeout(state.changeUpdate);
        state.changeUpdate = setTimeout(function() {
            var vp = cm.getViewport();
            if (state.from == state.to || vp.from - state.to > 20 || state.from - vp.to > 20) {
                updateInViewport(cm);
            } else {
                cm.operation(function() {
                    if (vp.from < state.from) {
                        updateFoldInfo(cm, vp.from, state.from);
                        state.from = vp.from;
                    }
                    if (vp.to > state.to) {
                        updateFoldInfo(cm, state.to, vp.to);
                        state.to = vp.to;
                    }
                });
            }
        }, opts.updateViewportTimeSpan || 400);
    }

    function onFold(cm, from) {
        var state = cm.state.foldGutter;
        if (!state) return;
        var line = from.line;
        if (line >= state.from && line < state.to)
            updateFoldInfo(cm, line, line + 1);
    }
});